Flexible beading or piping is commonly used in the fabrication of luggage as a means of separating and securing adjacent panels of the luggage container. The adjacent edge portions of the panels typically are sewn to legs or flanges of the piping which extend beneath the outer face of the panels, leaving exposed to view only the usual outer tubular portion of the piping. Depending upon the specific type of luggage involved, the piping may be reinforced, such as by hard wire or coil wire inserted into the tubular portion.
Whether or not the piping is reinforced, however, it tends to twist under the torsional stresses to which it is exposed in the corner areas, that is, where a straight run of piping changes direction about a relatively small radius. When twisting occurs the tubular portion of the piping reacts by tending to roll away from the adjacent luggage panel in the general direction of the twisting force, which can produce an unattractive uneven line of demarcation between the piping and the material of the adjacent panel. If the piping is not of uniform appearance throughout its length to begin with, the effect of the twisting is aggravated. For example, if the tubular portion of the piping were striped or the edges were colored differently from the rest of the exposed piping, the panel edges would appear to the viewer to be even more uneven.
It would be desirable, in view of the above problem areas, to provide a piping arrangement in luggage which overcomes the twisting problem described above. It would further be desirable to provide a piping design which allows a striped or multicolored piping to be used without endangering the overall appearance of the luggage due to the risk of twisting.